1. Field of the Invention
This invention relates to a recording and/or reproducing apparatus equipped with a cartridge lock mechanism used in combination with the recording and/or reproducing apparatus along with insertion and discharge of the disc cartridge.
2. Description of the Prior Art
As a medium of magnetic or magneto optical recording and reproducing, it has recently been known a magnetic or magneto optical disc.
In the U.S. Pat. No. 4,517,617 issued to Ohkawara, there is disclosed a disc cartridge comprising a hard jacket made from such material as plastic. The recording disc is substantially enveloped within the hard jacket for preventing damage and contamination of the disc itself and/or a recording area thereof which otherwise might occur when handling the disc or inserting it into the recording and reproducing apparatus. The hard jacket is provided with an aperture for insertion of a magnetic head mounted on the recording and reproducing apparatus when installed or loaded thereon. This head insertion aperture is normally closed by a shutter member slideably connected to the hard jacket, capable of preventing dust or fingerprints from entering through the head insertion aperture and therefore preventing contamination of the recording area of the disc. The shutter is provided with an access window which will allow the magnetic head to obtain access to the recording area of the disc, when the disc cartridge is loaded into the apparatus, for performing desired recording and/or reproducing operation.
With the system and apparatus disclosed in the above-referred U.S. Pat. No. 4,517,617 the shutter must be hand-manipulated to be laterally slid or opened before the disc cartridge is loaded into the apparatus, and after completing desired recording and/or reproducing operation and then discharging the disc cartridge out of the apparatus, the shutter must be closed by the operator's hand, which is troublesome. Further, fingerprints or other foreign matter would be adhered to the recording area of the disc when manipulating the disc cartridge for opening or closing the shutter.
This problem can be solved by a mechanism or device capable of automatically opening and closing the shutter as the disc cartridge is being inserted into the apparatus and discharted out of the apparatus. A typical one of such device is disclosed in the Japanese Utility-Model Publication Sho. 62-15895, which includes an operating lever rotatably mounted on the recording and reproducing apparatus and a cut-out notch formed at one side of the front edge of the shutter. The lever has at its one end a vertical pivot connected to the apparatus and at the other end a leading end in engagement with the notch of the shutter, said one end forward a direction opposite to the cartridge loading direction and the other end forward a direction opposite to the cartridge ejecting direction. During the cartridge loading or advancing operation, the engagement between the other end of the lever and the notch will cause the shutter to automatically open. While, in turn, the cartridge is being ejected away from the loaded position in the apparatus, the lever is rotated in the opposite direction due to a spring means connected to the apparatus, as well as another spring means connected between the shutter and the hard jacket for normally biasing the shutter toward the closed position, thereby automatically closing the shutter.
In the above-referred prior art device, the lever is arranged substantially above the shutter of the disc cartridge which is full-loaded in a holder of the magnetic recording and reproducing apparatus and there is required a considerable space for installing the shutter operating mechanism above the apparatus. In another type recording and reproducing apparatus for use in combination with magneto optical disc, however, as known, it will be necessary to mount a bias magnet on the apparatus in opposition to an optical head mechanism, across the disc in the cartridge installed in the loaded position, which becomes difficult or practically impossible to install the shutter operating lever substantially above the shutter as in the same manner in the prior art device.
We have attempted that the aforementioned prior art arrangement of the shutter operating lever be modified such that the pivot is mounted relatively in the backside of the apparatus with the engaging end oriented toward the cartridge loading direction. However, realization of such arrangement has been found difficult because a relatively great angle should be provided between the lever and the cartridge in order to actuate the shutter without a hitch, and the lever has a length in a limited range which is of necessity determined in correspondence with a stroke required for opening and closing the shutter. This will be especially difficult where the notch formed in the front edge of the shutter is arranged in close vicinity to the side face of the disc cartridge, leaving only a limited space available on the apparatus for mounting the pivot of the lever arranged outwardly of the side face of the disc cartridge. In the U.S. Pat. No. 4,688,123 issued to Sokol et al, there is also disclosed a shutter actuating mechanism. In particular reference to FIG. 7 to FIG. 9 of this prior art, as the disc cartridge 23 advances into the holder, rotation of the arm 120 will cause the shutter 27 to open. When the disc cartridge has reached the full-loaded position shown in FIG. 9, the leading end 121 of the arm 120 is engaged with the notch 31 formed in the front edge of the disc cartridge to the lock the disc cartridge in the full-loaded position. If the notch 31 or an equivalent element should not be formed in the front edge of the disc cartridge, the disc cartridge would tend to be discharged out of the cartridge holder by means of a spring for biasing the shutter toward the closed position and another spring for biasing the arm toward clockwise rotation.
It is therefore an object of the invention to provide a recording and/or reproducing apparatus equipped with a novel cartridge lock mechanism for locking a disc cartridge in a full-loaded position, which has much applicability to shape or construction of the disc cartridge rather than the prior art one.
Another object of the invention is to provide a novel recording and/or reproducing apparatus in which smooth insertion of a disc cartridge into a cartridge holder can be achieved.
In accordance with an aspect of the invention there is provided a recording and/or reproducing apparatus for performing the recording and/or reproducing operation with respect to a disc contained in a disc cartridge, comprising a holder for accommodating the disc cartridge; shutter actuating means for opening a laterally slidable shutter of the disc cartridge along with insertion thereof into the holder in a direction substantially perpendicular to the sliding direction of the shutter; a base for mounting thereon a head in opposition to one side of the disc and a spindle motor for rotating the disc, the base being displaceable between a first position retracted away from the holder and a second position close to the holder to make operative the head and the spindle with respect to the disc contained in the full-loaded disc cartridge in the holder; cartridge lock means for locking the disc cartridge in a full-loaded position, including a lock lever engageable with a corresponding engaging portion of the disc cartridge and first spring means for biasing the lock lever toward a direction in which engagement between the lock lever and the corresponding engaging portion is released; detect means for detecting that the disc cartridge has reached the full-loaded position in the holder; and control means operated in response to detection by the detect means to actuate the cartridge lock means against the first spring means to lock the disc cartridge in the full-loaded position and then to shift the base to the second position.